Membrane pump



y 1960 F. w. PL'EUGER ETAL 2,944,490

MEMBRANE PUMP Filed July 8. 1958 2 Sheets-Sheet 1 ATTORNEYS July 12,1960 F. W. I PLEUGER ETAL MEMBRANE PUMP 2 Sheets- Sheet 2 Filed July 8,1958 rum.

Friedrich Wilhelm Pleuger,Juthornst1-as se 80, Hamburgq Wandsbek,Gerniapy,,and Johann Schneider, Hamburg- Wandsbtek, Germany; s d; c mer. qr 1 1 4 4. eu e This invention relates to pumpsand is especiallycon-v. cernediwith submersible deep well-pumps 'cfn the type wherein aflexible pumping membrane divides a'pu'rnpmg, chamber from a workingchamber'filled with hydraulicfiuid and whe r'ein-the membrane is flexedby alternately increasing and-reducing the pressure of. the hydraulic:fluid in the working chamber.

'Membrahe pumps of-the character just described are now known tothe artbut, when pumping highly viscous liquids; they occasionally do not worlgsatisfactorily under conditions where thepumping memb'raneis flexed toorap 4 idly to give th'e highly, viscousl liquids suificient time inwhich to enter the pumping chamber. a

The principaliobject of th'e'pres'ent invention is to overcome thediflicultyjust-mentioned, vand weaccomplish this purpose by providing anauxiliary pump which. is placed between the working chamber and areservoir. containingihydraulic fluid whichi pumpris maintained incontinual operation so as to constantly deli-ver hydraulic fluid to theworking chamber; At the same time .we provide a valve system forcontrolling the movementsofthei pump-1 ing membrane, .so ;that,. when apredeterminedmemb-rane.

displacementrhas been, effected, especially themaximum displacement,communicationiwill; be established between the workingcha-mber and anoutlet tothe reservoirwhich-i, communications is maintained until thepressure of the hy-. draulic fluid isrsufiicientlyreduced to enable thepumping membraneto return to,its ini tiial or starting positionjf Thedisplacementof the auxiliary pumpflis designedto be con: siderably lessthan that; of thepumping membrane. and we Prov d .for operat ng/the vavesystem. her direct y by r emhrane mov ment or n ire lv hmug a on act:v ins sy t m ua dby e pumpingim mbr ne r. r gh a separate impulsegenerator. J A addit na tu e r fe e; vention is t e. nr9v si n f; naps pin y em. tween he lve bo y o he w th certain additional ifrii fc i favan ag s ich wil e i i v d f f 5 s") nes wil e b d sqrwibq incquue i withe ac mna r d awin s w ichillus Hate om what schemat cally wcp e e eeem o iments i heifi ntiqnr 7 Figure 1 of he rawin s l u tr tes;aheavvpitsub- 7 flheisuctign and; di char e passa s-c ease:

a1 sc t pn with pct Q s Figure 2 is a cross section on a somewhatenlarged scale takenapprogiir'nately as indicated by'theline 2-'2 on' Figure 1 Figure 3 is an axial section similar to that of Figure 1,

5 but"illus'tratingthe center portion'only of 'a'puinp'embodyingavariation of the invention. I

In the embodiment of Figure l, a composite cylindrical body iscontained'in a'pump casing-'1 said 'body being compqse'd' ofthreeisections Zia-3 and 4 which are secured to one Tanother by. meansof axially disposed :bbltszSr The" bolts 5 pass through axial holes.boredin the middle'body" section 3- and are screwed into a'threaded-holein body section 2 an',d .securedbylnuts 6in arecess'injhody section 4. g Boditsection z surroun ds the pumpingchamber 7 which chamber isconnectedin a, well knownma-nner to a suctionchamber 9 by means of a suction valve 8 and to a discharge line (notillustrated) by means of a checkjjvvalve 10; The

suction chamber 9 communicates through a strainer-like portion 11; 0fthe purnpcasing 1 withj the liquid to be pumped, generally the heavy'oilcontained in a well A lpumping' membrane 12 preferably in the form of a1QW i 1 w sw n s a d e w o y sections 2; an 'd,3 bellows membrane 12c'an be 'in- 5 fiatedby means of an-au riliaryfpump tobe described.serves to reduce the volume of the pumping and thereby forcestheliquid'contained therein 4 ien ing; 13 and jth electricalmotorarehousd in a body sec tion 1 6 w hfis' h ewise fastened in t he'pump casing.

Between Ody 'sectioiis 4 and ,1"6faneccentricshaft 17 1's mounted in aper enreuer bearings is, the" shaft I Tbeing were e m dium r 21; restsupon eccentric 20 o 'r' thei shafts 1 7,

v egpi'stoii' fiiof .aniauxiliarypump restsupon the tappefZl. To reducethe friction a bearing ball 24 is a arr-g betweentappetfilarid piston-23l -"l?he auxill v der 25 part of an inserted piece ,7 l 1 'sjplacfed 'ina -axial central, hole bored iri the body js lion The locationoflinserted piece 26 islfixed' by meansof a bushing 21 at ft-he m whichbushitig abuts anfinwardly projecting shoulder 3Z1 on the body section3; ThiscQnsr-uction formsthe-housing for a slide valve which is top bedescribedjbelow. TQsu port the insert12 6fa't the bottorn, anaddiitional bushing 28jis used,

thelower extremitfyfof which rests upon sleeve 22.

In order to keep piston23 and bearin glball 24in constant contact, withtappet 21 ,1a compression coil spring fdrmd arm otton i" of" pistonlii;Piston 2.3 ay be pro ded in t v naryflmanner with piston rings 30,. a"Th a lha y pump h mbe f defi i f v'pi 65 2s anidj cyliiider. 25cbmmrinieatesft rqugh hi ialypas':

ti d-b are a -sstevssl-;. etea uitable. are 2 12 5 225232: 7

tries. a beveled dnving'gar 1s; "The ball bear:

displaced llyiin'a sleeve}; in body sec the su iorijst r olie. Movement41 fit n ich is;

, in a check 'valve 40 in body section 16. Check valve 40,

like check valve 33, is fastened in place by a threaded fitting 42.

Above the axial passage 32 a slide valve is mounted within the housingsleeve 27, said slide valve consisting of an external sleeve 44 and aninternal sleeve 45. Fhe external sleeve 44 forms the actual valve andthis slides within the housing sleeve 27 in intimate contact therewith.In its extreme lower position as shown in Figure 1 the sleeve 44 closesport 47 of radially directed outlet passage 46 in body section 3. In itsextreme upper position the slide valve 44 uncovers said port 47 therebyproviding communication between the passage 32 and the outlet passage46.

As already mentioned, an internal valve sleeve 45 is provided .withinthe external sleeve 44. This internal sleeve has one or more axiallyorientated passageways 45a (see Figure 2) formed by the spacedprojections 45b on the internal sleeve 45. The axial passage 32communicates through the passageways 45a 'with the working chamber 48enclosed by the bellows membrane 12. Compression springs 51 and 52 areinserted between the projections 45b on the internal sleeve 45 and snaprings 49 and 50 inserted into the inside wall of external sleeve 44.These springs are constructed and arranged to hold the two interslidingvalve sleeves 44 and 45 in a central or middle position. Indeed, if thebellows membrane 12 is capable of an especially long stroke, springs 51and 52 may be supported at first at one end only so as not to bearagainst the internal sleeve 45 until the latter travels the desiredlonger distance. The inner sleeve 45 is firmly fastened to the bellowsmembrane 12 by the valve actuating rod 53 which thus constitutes anactual physical connection between the bellows membrane and the valve.To avoid binding of the slide valve, the lower end of the valveactuating rod 53 is provided with a ball 54 adapted to fit into thecenter bore of internal sleeve 45. This ball abuts on one side againstan annular internal shoulder 55 and on the other side against a setscrew 56 screwed into the sleeve. This construction creates a sort ofuniversal joint between the valve actuating rod 53 and the slide valvewhich functions to compensate for possible errors of alignment.

The radially directed outlet passage 46 is sealed at its outside end bya threaded plug 57 and communicates through an axial passage 58 in thebody section 3 with the hydraulic reservoir 41 which reservoir alsocontains the motor and the transmission. The suction check valve 40-42is beneath the normal oil level in the reservoir .as shown in Figure 1,the minimum oil level being shown by a dot and dash line marked with thelegend. However, the outlet for discharge passage 4746-58 may empty intothe reservoir 41 at a point above the oil level as indicated in Figure1.

The operation of the modification of our invention so far described isas follows: Assuming first that the pump is a submersible pump and hasbeen lowered into an oil well and that the pump motor has been startedand is rotating. The rotation of the motor is transmitted throughthebevel gears 15 and 19, to the eccentric shaft 17 and eccentric 20, thuscausing tappet 21 to be repeatedly lifted and dropped. This up-and-downmovement of tappet 21 is transferred through ball 24 to pump piston 23which constantly aspirates hydraulic fluid out of reservoir 41throughsuction check valve 4042 and passages 43-39'37. As mentioned previously,the reservoir is filled with hydraulic fluid at least to such an extentthat the bottom end of pipe 43 remains constantly immersed in thehydraulic fluid. Upon each compression stroke of pump piston 23, thehydraulic fluid is pumped out of auxiliary pumping chamber 31, throughcheck valve 3334 and the axial passageway's'45a in the internal slidevalve sleeve 45, into the working chamber 48. Membrane 12 thus inflatesand extends upward to reduce the volume of pumping chamber 7.

Since the displacement of pump piston 23 is quite considerably smallerthan the displacement of bellows membrane 12, a relatively large numberof strokes of auxiliary pump' 2325' are required before bellows membrane12 will be inflated to its maximum extension. In this maximum extensionof bellows membrane 12, the internal sleeve 45 of the slide valve islifted upward by valve actuating rod 53, relatively to the externalsleeve 44. The external sleeve 44 is at first held by friction in theslide valve casing 27. But as soon as the compression spring 51 issufficiently compressed by the relative move ment of the two valvesleeves 44 and 45 that its force exceeds the friction force between theexternal sleeve 44 and slide valve casing '27, the slide valve jumpsquite suddenly into its opposite extreme position.

In its opposite extreme position, the external valve sleeve 44 uncoversport 47 in slide valve casing 27, so that the hydraulic-fluid containedin working chamber 48 can flow out through passages 46 and 58 into thereservoir 41. The collapsing of the bellows membrane is favored by thepressure of the liquid flowing into pumping chamber 7.

In the downward travel of bellows membrane 12, valve actuating rod 53pushes the internal valve sleeve 45 downward. At first the externalsleeve 44 is held in its upper extreme position by friction. As valveactuating rod 53 moves downward, spring 52 is compressed until itfinally develops suflicient power to overcome the friction which holdsthe external valve sleeve in its upper extreme position and the slidevalve will suddenly spring into the other extreme position. In thisposition, outlet passage 46 is again closed, so that membrane 12 canagain be infiated for the next pumping stroke. It must also be mentionedthat, during the entire return or suction stroke of bellows membrane 12,the auxiliary pump 2325 is pumping hydraulic fluid out of reservoir 41into passage 32. This hydraulic fluid, however, immediately flows thesuction stroke 'of the membrane.

In the slow up-and-down movements of bellows membrane 12, the viscousliquid being handled is let in through suction valve 8 and pumpedthrough foot valve 10 into the discharge pipe.

' As will be appreciated the pump 23--25 will function satisfactorilyonly when the interior of membrane 12 is always supplied with oilarriving from chamber 41 via valve 40 and passages 39, 37, 32 and 45a.Since this oil comes from the reservoir 41, a vacuum will develop unlessan overpressure is present in the reservoir; In order to prevent this,membrane 12 is initially inflated with hydraulic fluid while thereservoir is exposed to atmosphericpressure. Then return of fluid to thereservoir will increase the air pressure in the reservoir so that at notime will avacuum exist in the system.

Another possibility for preventing the formaiton of a vacuum in thereservoir 41 consists in pumping air into the reservoir so thatacompressed air cushion is developed therein. However, under normaloperation, heating of the oil by the motor suflices to achieve thedesired pressurization of the reservoir. In the event that no aircushion is provided in the reservoir and the reservoir is completelyfilled with oil, an equalizing membrane or membranes of adequate sizemust be associated with the motor and to this end the wall of thehousing 1 adjacent to the reservoir 41 is formed with a flexiblediaphragm or diaphragms' subject on the inside to thepressure of the"hydraulic fluid within the chamber 41 and on, the other emer esidegrto-the ipressurelof the. oil in. thetwell." Suchdiaphragmsqvil-lcompensate forvariations .in the volume .ofi hydraulicfiuid' in=the chamber 41 by .flexing toward the reservoirastheoilispumped, to the membranelZ backfagain as the oilreturns to thereservoir.

In: the -modification illustrated'in Figurev 3ithe principleiofoperation is essentiallythe same as that dfethe I- For this reason the apartsxvwhichahave the same function; in thetWoembodi-fi ments are markedwith-the same reference characters embodiment 2 shown .in .Figure 1-.

The embodiment of Figure 3 difiers from that of Figure l mainly -in thefollowing-respect.- After. the. bellows membrane-12 isinflated and-anoutlet passageway to alsonsed to-pump thehydraulic -fluid-' back -=out--f the working chamber-4'8'into-thereservoin- In this embodiment=--theslide 'valve isactuated-as before-by-thevalveg actuating rod" 53-*but-thehydraulic fluid after passing through the axial passageway 32 isfed through radialpassages 58and an annular passage--59 in insertedpiece zfi 'anda radially-directed hole 60 inbody-section 3."

Hole 60 'communicates with anaxial passage til-which in turncommunicates through two connecting passages 62 and' 63'with'theinsideof the slide valve casing 27. The outlet passage 46,-which is connectedwith slide valve casing port 47, also communicates with passages 35;

throughja passage 64 and check valve 4%. An additional ogtle'tpassageisformed by 'a radial bore 65 which commtgnicates with'reservoir41 throughthe axialpasage 66; A'grecess-fl is provided in the outersleeve 44 of the slide valve, ,whichjcan connect outlet passage 365with:

letpass se Th e pump, system according toFigures 2 and 3 open ates, as,;follows:

PHtnppiston is constantlymoved up and down, the, same asgin thefirst-described embodiment. Hy-

draulic fluid is thus aspirated through check valve- 40,. and passage 46frdm-reservoir '41, and is discharged through passages 32, 58, 61 and 62into the working chamber 48. The membrane is inflated and the slidevalve actuated in the same manner as in the case of the first-describedembodiment. As soon as the slide valve has switched into the oppositeposition, the external valve sleeve 44 blocks the inlet port 62, so thati no more hydraulic fluid can be pumped into working chamber 48. Port 47is simultaneously uncovered, so that the hydraulic fluid can flow out ofworking chamber 48, through passages 46 and S. However--and this is theessential difference from the embodiment in Figure 1-the hydraulic fluidis positively pumped out of working chamber 48. Recess 67 in externalvalve sleeve 44 connects the discharge line 61 of auxiliary pump 2325directly to the outlet passage-"65. Since the check valve 40' isopposite outlet port 47, the auxiliary pump 23-25 now sucks thehydraulic fluid out through port 47, so that working chamber 48 isemptied very rapidly.

In order to makethe action of the slide valve as sudden as possible, theexternal valve sleeve 44 can also be slotted, in order to increase theratio between the breaklo'ose friction and the sliding friction betweenslide valve casing 27 and external valve sleeve 44. An additionalpossibility of holding the slide valve in its end positions consists inusing special holding magnets 68 and sometimes::encountered where theliquid -to be pumped a luralitytofi-pistons: can also. be.- used... Thecontrolling system vrepresented in the drawings; and, described aboverepresentslonlyrone..ofithe.many possibilities for the .con-r trolofzthe membraneflection. Instead of a sleeve-type.

;; slide valve:..control, the..outlet;ports-.can .be opened or;

closedintlike:manner-byztheirotationnof. a piston. -A toggle leven.type.;-.snapavalverisFalse-conceivable. In certain cases it may also beexpedient to provide, an electrical controlcin which the; membrane.then. merely aetuatesL-contacts.which icontrol; the.,. flow3..by: meansof electroniagnets or electriezmotorsrv ,A-s further. possibilityof-iithinvention. consists .in con-. trolling the membrane pump with an impulsegenerator. (e.g';,5rotary magnets) which-:controls; the valve movementLwith: a ver-yl precise,v adjustable rhythm; If such 'andmpulsegenerator.- is:.;electrical1y operated, it .canbe controlled eitherthrough-a second :cable .or through the motoncableLf The membrane stroke.is made .longer or shorter by slower orr morekrapidoperation .of theslide valvewhilethe auxiliarypump outputv remains the same, so.that-theg rate of flow ofltheheavyoil pumpcan be adjusted*withinwidelimits withoutctherchanges. If

an impulse generator isused,.provision can be made by means ofiavalve-coupled to.the membrane so that safety reliefaports are opened ifthemembrane: is excessively inflated. In this manner, damage tothemembrane or bellows scan be prevented-- in case T of improperoperation or failure of -the-impulse generator -etc.-

In conclusion, we wishto pointoutthat byour improve'ment we cancompletelyovercome the difficulties is of a very heavy visjcousnatureBy-employing anauxiliarypump as shown Y and 'described "together with a1 suitable valve control 'rne chanism therefor it; is possible 35 toeflfect: actuationorflexure of the-pumping membrane withgwh'ateverdegrees. of rapidity or slowness may be necessary withrelationtto theviscosity of the'liquid being pumped- -from-the -'well;. With structuresheretofore in use, as. previously .pointed-out,:the flexure of the mem-'brane was too rapid to give the highly=-viseousliquids suflicient timeto enter the pumping chamber, but with I the improvements disclosedherein this difiiculty can be overcome in the manner described.Furthermore, the valve system which we have adopted is so designed thatit connects the discharge line of the auxiliary pump to the outlet tothe reservoir during the suction stroke of the pumping membrane. In thismanner the return movernent of the membrane which is normally initiatedby the incoming pressure of the liquid being pumped is accelerated. t

. We claim:

l. A submersible deep well pump comprising a housing containing apumping chamber, a working chamber, aflexible pumping membraneseparating said chambers, hydraulic operating fluid in the workingchamber, a hydraulic fluid reservoir, an auxiliary pump having adischarge line delivering hydraulic operating fluid from the reservoirto the working chamber whereby to increase the pressure in the latterand effect flexure of the membrane in its pumping direction, thedisplacement of the auxiliary pump being substantially less than thedisplacement of the pumping membrane, a hydraulic fluid return line fromthe working chamber to the reservoir, a valve controlling the flow offluid through said return line, and means adapted to move-said valve topermit return of fluid from the working chamber to the reservoir upon apredetermined degree of fiexure of the pumping membrane in its pumpingdirection whereby to reduce the hydraulic pressure in the workingchamber and thereby to permit the pumping membrane to return to itsstarting position.

2. A pump according to claim 1 characterized by the fact that the meansfor moving the valve whichcontrols the fluid return line includes aphysical connection between the pumping membrane and the valve wherebymovement of the membrane is directly transmitted to the valve.

3. A pump according to claim 2 wherein the said valve is a frictionslide valve mounted to move in a suitable bore and, further, wherein theconnection between the mem' brane and the valve includes "a snap springmeans so constructed and arranged as to delay movement of the valveuntil the spring means has been tensed suificiently to overcome thebreak-loose friction between the valve and its bore. 7

4. A membrane pump according to claimv 2 wherein the valve is a slidevalve arranged coaxially with the axis of membrane movement and whereinthe connection includes a member articulated in the center of thepumping membrane.

5. A membrane pump according to claim 3 wherein the slide valve isarranged in a passageway which extends from the auxiliary pump to theWorking chamber and, further, wherein the slide valve is provided withaxially disposed passageways through which the hydraulic fluid is pumpedfrom the reservoir to the working chamber.

6. A membrane pump according to claim 3 wherein the valve is a slidevalve comprising two relatively movable sleeves, one within the other,with the inner one connected to the membrane and arranged to transferits axial displacements through the spring means to the other.

7. A membrane pump according to claim 2 wherein holding magnets areprovided which are adapted to hold the valve in its extreme positionswith a holding force not exceeding the maximum valve actuating force.

8. A membrane pump according to claim 1 character ized by the fact thatthe discharge line of the auxiliary pump is connected to the reservoirduring the suction stroke of the pumping membrane.

9. A membrane pump according to claim 8 wherein the auxiliary pump drawshydraulic fluid out of the working chamber during the suction stroke ofthe membrane.

10. A membrane pump according to claim 1 wherein 12. A membrane pumpaccording to claim 1 characterized by the fact that the pumping chamber,the pumping membrane, the valve, the auxiliary pump and the drivingmeans for the latter are aligned axially with one another and one abovethe other in a common housing for all.

13. A pump according to claim 1 wherein the auxiliary pump is a pistonand cylinder pump and wherein is provided a passageway for connectingthe cylinder with the reservoir and another passageway for connectingthe cylin- 'der with the working chamber together with a check valve ineach passageway.

- 14. A pump according to claim 13 characterized by the fact that amotor is provided for driving the piston of the auxiliary pump and thatsaid motor delivers its power 'to the piston through a tappet actuatedby an eccentric driven by the motor and, further, that a bearing ball isprovided between the piston and the tappet and a spring for maintainingcont-act between the ball and the tappet and between the ball and thepiston.

15. A submersible, deep-Well, pump comprising an elongated housingcontaining a well pumping chamber having intake and dischargeconnections, a working charnbar, a bellows membrane separating saidchambers, an

auxiliary pump, a hydraulic fluid reservoir, motor means for actuatingthe auxiliary pump, a connection between the reservoir and the workingchamber through which the auxiliary pump is adapted to deliver hydraulicfluid from the reservoir to the working chamber, a connection forreturning hydraulic fluid from the working chamber to the reservoir, avalve for controlling said return contint

